Efforts by Kiev Government to Maintain Control Have Stumbled

MOSCOW—Ukraine's acting president said Wednesday that the pro-Russian unrest that has shaken two eastern regions must not be allowed to spread to other parts of the country, and again blamed local police for failing to contain the insurgency.

Efforts by the new government in Kiev to maintain control in the troubled east have stumbled amid a renewed push by militants to seize government buildings before May 25 presidential elections...